I originally preferred Jekyll to Hugo and this explains why most of the 20 KDE websites are using Jekyll, but I recently fell in love with Hugo.

Hugo was a lot harder to learn, the template engine from Hugo felt very strange for myself coming from Django, Twig and the Jekyll template engines. The template lookup order is complex and for small website this complexity is unnecessary.

When building a large website (kde.org has more than 1400 pages) all these features make sense. I can organize my template in directories, enjoy fast generation time, separating the templating part from the content, create SCSS files for each pages that needs a special layout. There is also a (fast) JS bundler integrated into Hugo. Afaik Zola also doesn't support i18n and Jekyll has a few plugins for that but this is not a build-in functionality.